Wide Dynamic Range of a MEMS Differential Resonant Accelerometer with Asymmetric T-shaped Electrodes

This paper presents a wide-dynamic-range (DR) MEMS differential resonant accelerometer (DRA). Conventional MEMS DRAs have a structure in which T-shaped electrodes are placed symmetrically at the positions of maximum displacement of two resonant beams. Therefore, the resonance frequency difference between the two resonant beams is caused by manufacturing errors. When acceleration is applied, the resonant frequency of each mode fluctuates according to the scale factor (SF). When the resonance frequencies of each resonant mode are close to each other, the SF fluctuates due to the effect of mode localization, and this causes a problem that prevents accurate measurement. Therefore, in this study, the number of holes in the T-shaped electrodes is changed to make the structure asymmetric in order to intentionally differentiate the mass of the two T-shaped electrodes. This widens the DR compared to the conventional method, enabling measurements with a wide DR of +40G to -40G.